This invention is related to medical ultrasonic diagnostic imaging, and more specifically to methods that register multiple ultrasonic image frames in a 3-D spatial model.
When an ultrasound transducer is moved along a patient's body, multiple image frames (e.g., B-mode image frames) can be acquired sequentially. The spatial coordinates of each image frame can be determined using any of various prior-art approaches. For example, image correlation methods can be used to develop frame coordinates in the frame of reference of the imaged tissue. See, for example, U.S. patent application Ser. Nos. 08/621,561, 08/807,998, and 08/916,585, all assigned to the assignee of the present invention. Other well-known approaches for determining frame coordinates include image decorrelation methods (Friemel, et al U.S. Pat. No. 5,899,861) mechanical positioning devices for the transducer (McCann, et al. "Multidimensional Ultrasonic Imaging for Cardiology" (Proc. of IEEE, 76, 9, pp 1063-1072, September, 1988) and magnetic or other sensors for locating the transducer in space (Schwartz U.S. Pat. No. 5,474,073). Once the ultrasonic image frames and the frame coordinates have been obtained, the frames can be registered in a 3-D spatial model.
Conventional systems as described above exhibit systematic errors in the 3-D spatial model due to the fact that the transducer is in motion as the image frames are acquired, and each frame includes data acquired over a large number of separate ultrasound beams that are fired sequentially in time. A need presently exists for an improved approach that reduces such errors.